Variation of major cations against salinity in the Yangtze River estuary

Surface and bottom water samples in the Yangtze River estuary were collected in the summer of 2001, following estuarine mixing procedure. Major ions Mg²⁺, Ca²⁺, Na⁺ and K⁺ were determined. The results show that pollution has little influence on pH situation in the Yangtze River estuary. Concentrations of major ions in mixing zone increase with salinity and the ratio of dissolved Ca/Mg decrease. Change in major ions in the Yangtze River estuary can be simulated by a linear mixing model between riverine and sea waters. There is no obvious difference between surface and bottom waters in major ion compositions.